Hi don’t know if anyone can help.

Starter motor for a countax ride on lawnmower K14 1992 briggs and Stratton vanguard 14hp engine



2 months ago it would not start, replaced the solenoid, a new battery then the starter. Replaced starter and it worked. Three times now it will not start – sit on tractor turn key the solenoid clicks but the starter will not turn. I charged the battery up on a trickle charge, then used the boost button – nothing. The battery voltage across the terminals is 13.1V. I have checked all the cables, put a car lead from batteryN to starter casing, no different. I have checked both safety switches and shorted them out they are both fine. Put a car lead from battery live to starter terminal – nothing. Checked all fuses. Visibly checked PCB, no smell, no burning. Took plug out to ensure petrol had not flooded cylinder – no difference. The mower had a full service and changed both drive belts in Jan. The engine can be turned by hand. Oil level ok and like new. The mower has no rust as it gets cleaned and painted annually. i have checked all the leads all tight and no verdigree.

The first time it did this it started on boost after trickle charging for an hour. The second time this did not work – I took off the starter and did a bench test it was fine – it threw the cog and looked fine. Put it back on and the machine started. Yesterday it started and ran for 1.5hrs. I stopped the machine to clean it, then tried to start it, it turned over a few times battery drained then back to just a click from the solenoid. Pushed it back into the garage and trickle charged it for 2 hrs – tried the boost start – nothing, the odd thing is the battery when trickle charging starts off in the green and only takes about 30mins to show full charge, also the battery green light stays green. When sat on the machine with clutch depressed when I turn the key the multi-meter between the battery N and the live terminal on the starter goes from 0 to 12.76V, but the engine does not turn.

The battery charger is a large Clarke semi commercial unit.

took off new starter and put on old one. it turned over a few times then back to the solenoid just clicking no action from starter.

Took off old starter, dismantled, tested between segments all same ohms, tested segments to ground all ok, brushes fine clean and no arcing. Replaced starter no good.

As a last resort replaced PCB board – no change

Bench tested both starters again – nothing.

It could be that both are shot, the old starter was only 4 years old [-the symptoms of the old starter not working and the new one not working were identical. I cannot find any info on what would cause a starter motor to fail as they are a relatively simple bit of kit


any advice would be appreciated
 
Is there a safety switch under the seat that only allows engine to start when someone sits?
Maybe that’s not making contact.
 
If the battery voltage remains at 12.76V then would think that starter motor not engaging, would expect voltage to fall to 10.5/11V.
no the starter motor is not engaging - neither the old or new starter move on a bench test - suggesting they are both duff, but is something causing them to fail?
 
Its a strange one alright, presume nothing daft like a 6V starter or reversed battery polarity, can you try a different battery.
If its the normal pre engaged type starter then you might have one wire going from start button to the solenoid, there will be a much heavier cable direct from the battery to the main starter terminal, when the start button is pressed the solenoid is energised and engages the pinion with the ring gear and also closes a contactor to stat turning the starter to start the engine. You could check the resistance between the solenoid coil + and the body of the starter and see if you have continuity or a fairly low resistance as I think that the solenoid coil is also connected internally on the negative side to slowly turn the pinion while also engaging it before the main contacts close.
 
Its a strange one alright, presume nothing daft like a 6V starter or reversed battery polarity, can you try a different battery.
If its the normal pre engaged type starter then you might have one wire going from start button to the solenoid, there will be a much heavier cable direct from the battery to the main starter terminal, when the start button is pressed the solenoid is energised and engages the pinion with the ring gear and also closes a contactor to stat turning the starter to start the engine. You could check the resistance between the solenoid coil + and the body of the starter and see if you have continuity or a fairly low resistance as I think that the solenoid coil is also connected internally on the negative side to slowly turn the pinion while also engaging it before the main contacts close.
hi, tried a different battery, the starter is not pre engaged, it throws th cog into the flywheel at least it used to! the solenoid is a seperate unit when the ignition is turned on a voltage goes to it, the other half of the coil is grounded. you can hear the contactor working and a multimeter shows that it puts the voltage to the starter motor.
it is strange, i am fairly convinced that both starter motors have failed - but why is the puzzle?
cutting an acre of grass with a push mower is not great!
 
If its throwing a cog onto the flywheel then the starter motor must be turning fast enough initially at any rate to make the pinion move along the shaft?. What is the resistance across the terminals? I suppose it should read nearly zero ohms, if burned out then probably infinity.
 
Looking at a schematic it just looks like a inertia type starter motor so no pre engaging.
that is correct, i posted a breakdown of the starter earlier - there is nothing to it -static magnets, an armature which tested fine and 4 brushes which were in good condition and all the springs were intact
 
hi, tried a different battery, the starter is not pre engaged, it throws th cog into the flywheel at least it used to! the solenoid is a seperate unit when the ignition is turned on a voltage goes to it, the other half of the coil is grounded. you can hear the contactor working and a multimeter shows that it puts the voltage to the starter motor.
it is strange, i am fairly convinced that both starter motors have failed - but why is the puzzle?
cutting an acre of grass with a push mower is not great!
Hi Stephen, have you solved the starter engagement?
I Have exactly same issue and a similar field to mow...
Contactor clicks, starter fly's up but engine turns to slow to start. Battery vitals are fine.
Starter, checks out ok, & it fly's to engage.
I am going to try with the plug out to see if engine turns over faster with less resistance.
Next, I will change dc contactor to eliminate this as an issue.
Please let me know if you got to bottom of problem?
J
 
it turned out new starter was duff. if petrol is getting into chamber (dirt in carb) then it will create high resistance.
use car jump leads to bypass other leads. one from battery to starter body, one from live battery and just touch the live input on starter. this will show if any permanent leads are duff i suspect solenoid is ok
s
 

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starting problem on countax ride on lawnmower
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